A New Clathrate Featuring a Spiro-Type Ammonium Host. X-Ray Structure of the Inclusion Compound with Chloroform

A new onium salt host molecule 1 featuring a spiro-type ammonium backbone was synthesized and shown to form a crystalline inclusion compound with chloroform, 1 · chloroform (1:2), the crystal structure of which is reported. The host molecular interactions including C–H···Br, Cl···Cl and aromatic stacking contacts are typical of the packing structure.Supplementary Data relevant to this publication have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication No. CCDC 229358.This revised version was published online in July 2005 with a corrected issue number.     

Counting of labelled tyrosine molecules in hydrophobic yoctolitre wells filled with water

Time-dependent radioactivity and solid-state 13C-NMR measurements of tyrosine entrapped in water-filled yoctolitre (10(-24) L) wells with hydrophobic walls are reported; the results indicate that such wells induce the formation of quasi solid tyrosine if they are brought in contact with 0.1 M solutions of this edge amphiphile.     

Low-temperature resistance anomaly at SrTiO3 grain boundaries: evidence for an interface-induced phase transition

Variable temperature transport between 1.4 and 300 K, structural imaging, and theoretical calculations were used to characterize the properties of electrically active 24 degrees and 36.8 degrees [001] tilt SrTiO3 grain boundaries with 0.1 at. % niobium doping. An anomaly in boundary resistance and capacitance characteristics typical of a positive temperature coefficient effect is observed. This behavior is indicative of interface-induced dipole ordering. The detailed atomic structures of these grain boundaries were determined from a comparison of ab initio calculations and Z-contrast TEM images. The number of excess electrons at the boundaries determined experimentally and theoretically agrees and is associated with the boundary structural units.     

Picosecond-pulse-induced two-photon fluorescence enhancement in biological material by application of grating waveguide structures

We report enhancement of two-photon fluorescence (TPF) excitation in fluorescent dyes and fluorescently labeled biomolecules by exploiting the optical properties of double grating waveguide structures (DGWSs). Picosecond laser pulses generate a large evanescent field based on the guided mode phenomenon in the resonant DGWSs, which induces strong TPF signals from fluorescent dyes at the waveguide surface. By recording enhanced TPF signals of Rhodamine B and Lucifer Yellow under resonance conditions, a detection sensitivity of concentrations of approximately one dye molecule per 0.1 microm2 was achieved. For the first time to our knowledge, enhanced TPF signals of a Lucifer Yellow-labeled biomolecule (human self-peptide) in an aqueous environment are demonstrated. These results strongly encourage the use of DGWSs as enhancement platforms in modern biophysics and biotechnology for investigations of biological membranes and cells.     

Hilbert spaces of holomorphic functions on bounded domains

In [6] the notion of Hilbert-Stein complex spaces was introduced. The purpose of this note is to illustrate the conjecture that any Stein space whose points can be separated by bounded holomorphic functions, is Hilbert-Stein. We prove this fact for the following kinds of bounded domains of holomorphyD in C ⁿ : 1)n=1 and ₁(D) is finitely generated, 2) the group of automorphisms ofD in the compactopen topology is compact, 3)D is strongly pseudoconvex with smooth boundary andn2, 4)D is symmetric of type I.     

Über Fluoride mit vierwertigem Kupfer: Cs2[CuF6]

Chlorides Ag₃MCl₆ have been obtained with M = Dy? Lu, Y, Sc from AgCl/MCl₃ mixtures (sealed Pyrex ampoule, 380°C, 8 d). They crystallize like Na₃GdCl₆-I with a “stuffed” LiSbF₆-type structure (R3 , Z = 3). Thermal expansion was followed for Ag₃HoCl₆ and Ag₃YCl₆ and is remarkably different from that of Na₃GdCl₆-I.